Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

pallet-migrations: fix index access for singluar migrations #5695

Merged
merged 4 commits into from
Sep 13, 2024
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 15 additions & 0 deletions prdoc/pr_5695.prdoc
Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
title: 'pallet-migrations: fix index access for singluar migrations'
doc:
- audience: Runtime Dev
description: |-
Discovered a bug in the migrations pallet while debugging https://github.com/paritytech/try-runtime-cli/pull/90.
It only occurs when a single MBM is configured - hence it did not happen when Ajuna Network tried it...

Changes:
- Check len of the tuple before accessing its nth_id
- Make nth_id return `None` on unary tuples and n>0
crates:
- name: pallet-migrations
bump: patch
- name: frame-support
bump: patch
7 changes: 4 additions & 3 deletions substrate/frame/migrations/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -678,7 +678,7 @@ impl<T: Config> Pallet<T> {
return Some(ControlFlow::Break(cursor))
}

let Some(id) = T::Migrations::nth_id(cursor.index) else {
if cursor.index >= T::Migrations::len() {
// No more migrations in the tuple - we are done.
defensive_assert!(cursor.index == T::Migrations::len(), "Inconsistent MBMs tuple");
Self::deposit_event(Event::UpgradeCompleted);
Expand All @@ -687,8 +687,9 @@ impl<T: Config> Pallet<T> {
return None;
};

let Ok(bounded_id): Result<IdentifierOf<T>, _> = id.try_into() else {
defensive!("integrity_test ensures that all identifiers' MEL bounds fit into CursorMaxLen; qed.");
let id = T::Migrations::nth_id(cursor.index).map(TryInto::try_into);
let Some(Ok(bounded_id)): Option<Result<IdentifierOf<T>, _>> = id else {
defensive!("integrity_test ensures that all identifiers are present and bounde; qed.");
Self::upgrade_failed(Some(cursor.index));
return None
};
Expand Down
25 changes: 25 additions & 0 deletions substrate/frame/migrations/src/tests.rs
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,31 @@ use frame_support::{pallet_prelude::Weight, traits::OnRuntimeUpgrade};
#[docify::export]
#[test]
fn simple_works() {
use Event::*;
test_closure(|| {
// Add three migrations, each taking one block longer than the previous.
MockedMigrations::set(vec![(SucceedAfter, 2)]);

System::set_block_number(1);
Migrations::on_runtime_upgrade();
run_to_block(10);

// Check that the executed migrations are recorded in `Historical`.
assert_eq!(historic(), vec![mocked_id(SucceedAfter, 2),]);

// Check that we got all events.
assert_events(vec![
UpgradeStarted { migrations: 1 },
MigrationAdvanced { index: 0, took: 1 },
MigrationAdvanced { index: 0, took: 2 },
MigrationCompleted { index: 0, took: 3 },
UpgradeCompleted,
]);
});
}

#[test]
fn simple_multiple_works() {
use Event::*;
test_closure(|| {
// Add three migrations, each taking one block longer than the previous.
Expand Down
9 changes: 6 additions & 3 deletions substrate/frame/support/src/migrations.rs
Original file line number Diff line number Diff line change
Expand Up @@ -673,7 +673,8 @@ pub trait SteppedMigrations {

/// The `n`th [`SteppedMigration::id`].
///
/// Is guaranteed to return `Some` if `n < Self::len()`.
/// Is guaranteed to return `Some` if `n < Self::len()`. Calling this with any index larger or
/// equal to `Self::len()` MUST return `None`.
fn nth_id(n: u32) -> Option<Vec<u8>>;

/// The [`SteppedMigration::max_steps`] of the `n`th migration.
Expand Down Expand Up @@ -777,8 +778,10 @@ impl<T: SteppedMigration> SteppedMigrations for T {
1
}

fn nth_id(_n: u32) -> Option<Vec<u8>> {
Some(T::id().encode())
Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This was the actual issue

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Oh and this was not overwritten for a single migration that's not part of a tuple, right?

fn nth_id(n: u32) -> Option<Vec<u8>> {
n.is_zero()
.then_some(T::id().encode())
.defensive_proof("nth_id should only be called with n==0")
}

fn nth_max_steps(n: u32) -> Option<Option<u32>> {
Expand Down
Loading